1. Field of Invention
The present invention relates to a backlight module. More particularly, the present invention relates to a side-entrance lighting structure of a backlight module.
2. Description of Related Art
Liquid crystal display (LCD) panels are light and thin, and have many advantages that include low power consumption. LCD panels are applied in many electronic products. Since liquid crystals themselves do not emit light, an external light source is necessary for an LCD panel. Therefore, a backlight module is one of key components for an LCD panel.
Generally speaking, the backlight module light source can mainly comprise a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED). LED light sources have advantages including high brightness, excellent color purity, a long life cycle, no mercury concentration, and good reliability. The backlight module structure could be a bottom lighting structure or an edge lighting structure.
Bottom lighting structures are normally used in large size backlight modules. After light is emitted and reflected through a reflector, the light is dispersed uniformly through a diffuser. Advantages of a bottom lighting structure include high luminance, good viewing angle, and simple structure. However, bottom lighting structures are thick and heavy, and increase the power consumption of the backlight module.
Edge lighting structures are generally used in small or medium size backlight modules. Light from an edge lighting structure is emitted to a side section of a backlight module. The advantages of an edge lighting structure include a light weight, a small volume, and a low power consumption. However, electrical elements or optical sheets are easily damaged when the light source is too close to the optical sheets during the installation or replacement of the light source. However, optical efficiency decreases when there is an excessively large space between optical films and light source.